Phenotypic, cytogenetic, and molecular marker analysis of Brassica napus introgressants derived from an intergeneric hybridization with Orychophragmus

PLoS One. 2019 Jan 10;14(1):e0210518. doi: 10.1371/journal.pone.0210518. eCollection 2019.

Abstract

Aneuploids of a single species that have lost or gained different chromosomes are useful for genomic analysis. The polyploid nature of many crops including oilseed rape (Brassica napus) allows these plants to tolerate the loss of individual chromosomes from homologous pairs, thus facilitating the development of aneuploid lines. Here, we selected 39 lines from advanced generations of an intergeneric hybridization between Brassica rapa and Orychophragmus violaceus with accidental pollination by B. napus. The lines showed a wide spectrum of phenotypic variations, with some traits specific to O. violaceus. Most lines had the same chromosome number (2n = 38) as B. napus. However, we also identified B. napus nulli-tetrasomics with 22 A-genome and 16 C-genome chromosomes and lines with the typical B. napus complement of 20 A-genome and 18 C-genome chromosomes, as revealed by FISH analysis using a C-genome specific probe. Other lines had 2n = 37 or 39 chromosomes, with variable numbers of A- or C-genome chromosomes. The formation of quadrivalents by four A-genome chromosomes with similar shapes suggests that they were derived from the same chromosome. The frequent homoeologous pairing between chromosomes of the A and C genomes points to their non-diploidized meiotic behavior. Sequence-related amplified polymorphism (SRAP) analysis revealed substantial genomic changes of the lines compared to B. rapa associated with O. violaceus specific DNA bands, but only a few genes were identified in these bands by DNA sequencing. These novel B. napus aneuploids and introgressants represent unique tools for studies of Brassica genetics and for Brassica breeding projects.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aneuploidy
  • Brassica napus / genetics*
  • Brassicaceae / genetics*
  • Chromosomes, Plant
  • Crosses, Genetic
  • Cytogenetics
  • Genome, Plant
  • Hybridization, Genetic*
  • Phenotype
  • Plant Breeding

Grant support

This work was supported by the National Key Research and Development Program of China to XH (grant no. 2016YFD0100202, http://service.most.gov.cn/2015tztg_all/20160622/1104.html). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.